1. Field of the Invention
The present invention relates to a system in which a telephone line is used for checking an electronic apparatus and performing repair, adjustment, and the like thereof from a remote location.
2. Description of the Related Art
One system controlling electronic apparatus such as a VTR, has been disclosed in the gazette of EP 0,467,305, Al.
This system is called LANC (Local Application Control Bus System) and in this system electronic apparatus such as a VTR, a single-unit video camera-recorder, or tuner is controlled by peripheral equipment such as an edit controller or a remote controller. The system, by setting an electronic apparatus in a service mode, can detect a failure in the electronic apparatus and adjust it. Below will be described a checking and/or adjusting system for electronic apparatus using the LANC with reference to FIG. 12 to FIG. 14.
In a checking and/or adjusting system for electronic apparatus shown in FIG. 12, reference numeral denotes a VTR as an electronic apparatus to be checked and adjusted, 12 denotes an adjusting apparatus for making the check and adjustment, and 4 denotes a LANC cable.
The VTR 1 comprises a microcomputer 11, a signal processor 12, an EEPROM 13, and an input/output interface 14. The microcomputer 11 has a function to execute system control of the VTR 1. The signal processor 12 is a video signal processor, an audio signal processor, a reception circuit, or the like. The EEPROM 13 stores various data for controlling the signal processor 12, such as white balance setting data, EVR (electronic volume) setting data, receive frequency setting data, and patch correction data of a ROM (not shown) in the microcomputer 11. The input/output interface 14 has a function to make data conversion from serial data on the LANC cable 4 to parallel data of the microcomputer 11 and vice versa.
The adjusting apparatus 12 comprises a microcomputer 121, keys 122, a display 123, and an input/output interface 124. The microcomputer 121 has a function to execute system control of the adjusting apparatus 12. The keys 122 are for inputting various commands and data necessary for the check and adjustment. The display 123 displays commands and data input from the keys 122, responses from the VTR 1, and the like. The input/output interface 124, similarly to the input/output interface 14, has a function to make data conversion from serial data on the LANC cable 4 to parallel data of the microcomputer 121 and vice versa.
FIGS. 13(a)-13(d) show a data format used in the LANC. As shown in this diagram, a set of 8-word data is transmitted in each 1-field period of a video signal. Of the 8 words, word 0 to word 3 are used for transmitting various commands and data from peripheral equipment such as an adjusting apparatus to electronic apparatus such as a VTR, while word 4 to word 7 are used for transmitting statuses and various data of the electronic apparatus from the electronic apparatus such as a VTR to the peripheral equipment such as an adjusting apparatus. Each word is formed of 8 bits and has a start bit and a stop bit inserted at its beginning and end, respectively.
Referring now to FIG. 14, a procedure to rewrite data stored in the EEPROM 13 within the VTR 1 in the checking and/or adjusting system for electronic apparatus arranged as described above will be described.
First, the VTR 1 and the signal processor 12 are linked via a LANC cable 4. Then, the keys 122 of the adjusting apparatus 12 are operated to set a code for setting the mode to the service mode, a command to read data stored in the EEPROM 13, and the location to be read (page, address, etc.) in the words 0 to 3 shown in FIGS. 13(a)-13(d). These code, command, data, and the like are successively transmitted to the VTR 1. Upon receipt of the code to set the mode to the service mode, the VTR 1 sets information indicating that the mode has been set in the service mode to the word 4 and, at the same time, reads the data stored in the EEPROM 13 into a RAM (not shown) within the microcomputer 11. Further, upon receipt of the command to read the data and the information indicating the location to be read, the VTR 1 reads the data corresponding to the location from the RAM and sets the data read and the location read (page, address, etc.) in the words 5 to 7. Such mode information, data read, and the like are successively transmitted to the adjusting apparatus 12. The adjusting apparatus 12, receiving such transmitted data and the like and checking the contents, can determine the position of failure. The setting of the position to be read for determination of the position of failure may be made manually by a serviceman or automatically by a program in the microcomputer 121.
When the position of failure is determined as described above, then, the keys 122 are operated so that a command to rewrite the content of the EEPROM 13, the location (page, address, etc.) of the EEPROM 13 where the content is to be rewritten, and the data for rewriting (these will hereinafter be called the data rewriting command etc.) are set in the word 1 to word 3. The data rewriting command etc. are successively transmitted to the VTR 1. The microcomputer 11 of the VTR 1, upon receipt of the command to rewrite the content of the EEPROM 13, sets a write protection releasing flag. When it receives the data for rewriting etc., it rewrites data on the RAM and copies the data into the EEPROM 13. While the data are being rewritten, it sets a status indicating that data are being rewritten in the word 5, and when the rewriting is completed, it sets a status indicating that the rewriting is completed. In the words 6 and 7, there are set the data on the RAM, hence, the data etc. rewritten when the rewriting has been completed. The adjusting apparatus 12 receives the status indicating completion of the rewriting and displays it on the display 123. Therefore, the serviceman can confirm that the content of the EEPROM 13 corresponding to the position of failure is rewritten.
While, for convenience, it is shown in FIG. 14 such that the adjusting apparatus 12 transmits the service mode setting code, command to read data, data rewriting command etc., separately, one after another, in reality, for example once the service mode setting code is set in the word 0, all of them are transmitted to the VTR 1 every field as shown in FIGS. 13(a)-13(d). Alternatively, the command to read data and the like can be transmitted during the period of the field for transmitting the service mode setting code at the start.
In the above described checking and/or adjusting system of the related art, however, the peripheral equipment for performing the check and adjustment and the electronic apparatus as the object of the check and adjustment are directly linked through a LANC cable and the electronic apparatus is checked and adjusted by having commands and data transmitted and received between them. Hence, there has been a problem that it is impossible to perform the check and adjustment from a remote location. Accordingly, when the electronic apparatus gets out of order, it has been necessary for the user to take it to a service company or for the serviceman to visit the user's location.